The present invention relates to a high speed laser drilling system, and more particularly to a method of operating a laser drilling system to achieve improved laser hole resolution without sacrificing product advancement speed.
Laser systems are often employed to create uniformly spaced holes in a product material such as an advancing web, and such systems are advantageous because of the high product advancement speed and laser hole resolution that can be achieved. Similarly configured systems are used to create holes in continuously fed sheets and in products advanced on a conveyor. However, there are particular hole size and spacing configurations that limit the product advancement speed and/or laser hole resolution because of the constraint of laser turn-on and turn-off times. Specifically, where holes are spaced a relatively large distance apart in comparison to the size of the holes, laser turn-on and turn-off times can limit the speed of product advancement or the resolution of the laser holes. For example, if the product advances at too high of a speed, the laser may remain on for too long and therefore create too large of a hole. Therefore, a method of operating a laser drilling system that enables high laser hole resolution without sacrificing product advancement speed would be a significant improvement in the art.
The present invention is a method and apparatus for high resolution, high speed laser drilling of an advancing product. A product is advanced in a predetermined product advancement path at a web advancement speed. A laser-generating source provides a pulsed laser beam having a laser-on time and a laser-off time. The laser beam is reflected to direct a focal point of the laser beam onto the web. The focal point of the laser beam is moved in a direction of the product advancement path during the laser-on time and is moved in a direction opposite to the direction of the product advancement path during the laser-off time. The present invention is therefore able to improve laser drilling resolution for a given product advancement speed.